Personalized Medicine Redefines How Docs Treat Cancer

Casey Carleton, 32, is pictured here with his wife, father and three children. Carleton is now in remission after entering the MD Anderson experimental cancer treatment trial. Instead of treating his melanoma specifically, doctors tailored drug treatment to the specific genetic mutation causing his cancer.

Imagine a world in which cancer isn't diagnosed according to where it is found on the body but according to genes found in the tumor itself. Patients with skin cancer, colon cancer and parathyroid cancer, for example, might be reclassified as "B-Raf mutation" patients and be treated with the same mutation-specific drugs. Instead of receiving breast cancer-specific chemotherapy, a breast cancer patient might join those with ovarian, uterine and cervical cancer to receive drugs targeted at inhibiting the PIK3CA mutation found in their tumors.

This paradigm shift may seem revolutionary, but more than a thousand patients have already been treated this way by researchers at MD Anderson Cancer Center in Houston.

In the largest study of its kind, researchers enrolled more than 1,150 cancer patients in phase I clinical trials to test the effectiveness of genetically targeted drug therapies -- an approach known broadly as personalized medicine. The results of these clinical trials will be presented today at the American Society for Clinical Oncology conference in Chicago.

The trial patients have bladder, breast, cervical, colorectal, gastric, liver, lymphoma, lung, melanoma, ovarian or any number of other cancers, but cancer location didn't necessarily determine their treatment. Patients were treated according to which of 12 known genetic mutations researchers found in their tumors. For instance, a patient in a trial for the PIK3CA mutation might include those with ovarian, cervical, uterine or breast cancer.

In a world used to dividing up cancers by body part and assigning colored ribbons accordingly, the gene approach to treatment marks a fundamental change in the way we even think about cancer.

"We classify cancers according to where they start, but each cancer is probably many types of cancer. The bigger picture is what are the genetic abnormalities that make that cancer grow. We've known about these mutations for a long time, but it's only recently that we have new drugs to target [them]," says Dr. Gerald Falchook, assistant professor in the department of investigational cancer therapeutics at MD Anderson.

The concept of genetically personalized cancer treatment has been a goal among cancer researchers for years, but the MD Anderson trial offers hope that widespread use of these kinds of treatments are within reach.

"Traditional treatments for cancer, such as chemotherapy, are one size fits all. All lung cancer patients might receive the same type of chemotherapy," says Falchook. While this approach can be effective, it ravages the patient's body by attacking all of a patient's cells in hopes of killing the cancer.

Genetically targeted therapy, on the other hand, isolates the abnormal proteins within the cell that only occur in the cancerous tumor itself. "This has led to the development of drugs that are less toxic than traditional chemotherapy," he says. And for patients with identifiable genetic mutations, this type of treatment can be effective when nothing else has worked.